1. Field of the Invention
The present invention relates to emulsified water-blended fuel compositions, more particularly to water-blended fuel compositions containing a liquid fuel, water, an emulsifier, and an amine salt which may function as an emulsion stabilizer or combustion modifier. In one embodiment of the invention, the composition further comprises an organic cetane improver, and in one embodiment an antifreeze.
2. Description of the Related Art
Internal combustion engines, especially diesel engines using a mixture of water and fuel in the combustion chamber can produce lower NOx, hydrocarbon and particulate emissions per unit of power output. Water is inert toward combustion, but acts to lower peak combustion temperatures which results in less NOx formation. Exhaust Gas Recirculation (EGR) works on the same principle (i.e., inert materials tend to lower peak combustion temperatures and hence reduce NOx). Water can be separately injected into the cylinder, but hardware costs are high. Water can also be added to the fuel as an emulsion. However, emulsion stability has historically been a problem.
It would be advantageous to provide a water-blended fuel composition that has improved emulsion stability. The present invention provides such an advantage.
U.S. Pat. No. 5,669,938, Schwab, Sep. 23, 1997, discloses a fuel composition which consists of (i) a water-in-oil emulsion comprising a major proportion of a hydrocarbonaceous middle distillate fuel and about 1 to 40 volume percent water, (ii) a CO emission, and particulate matter emission reducing amount of at least one fuel-soluble organic nitrate ignition improver, and optionally containing (iii) at least one component selected from the group consisting of di-hydrocarbyl peroxides, surfactants, dispersants, organic peroxy esters, corrosion inhibitors, antioxidants, antirust agents, detergents, lubricity agents, demulsifiers, dyes, inert diluents, and a cyclopentadienyl manganese tricarbonyl compound.
European Patent EP 0 475 620 B1, Sexton et al., Aug. 11, 1995, discloses a diesel fuel composition which comprises: (a) a diesel fuel; (b) 1.0 to 30.0 weight percent of water based upon said diesel fuel; (c) a cetane number improver additive, present in an amount up to, but less than, 20.0 weight percent based upon said water, said additive being selected from an inorganic oxidizer, a polar organic oxidizer and a nitrogen oxide-containing compound; and (d) 0.5 to 15.0 wt. % based on the diesel fuel of a surfactant system comprising (i) one or more first surfactants selected from surfactants capable of forming a lower phase microemulsion at 20° C. when combined with equal volumes of the fuel and water at a concentration of 2 grams of surfactant per deciliter of fuel plus water, which microemulsion phase has a volume ratio of water to surfactant of at least 2; at least one said first surfactant being an ethoxylated C12-C18 alkyl ammonium salt of a C9-C24 alkyl carboxylic or alkylaryl sulfonic acid containing 6 or more ethylene oxide groups; and (ii) one or more second surfactants selected from surfactants capable of forming an upper phase microemulsion at 20° C. when combined with equal volumes of the fuel and water at a concentration of 2 grams of surfactant per deciliter of fuel plus water, which microemulsion phase has a volume ratio of water to surfactant of at least 2; at least one said surfactant being an ethoxylated C12-C18 alkyl ammonium salt of C9-C24 alkyl carboxylic or alkylaryl sulfonic acid containing less than 6 ethylene oxide groups; the said first and second surfactants being present in a weight ratio which forms with components (a), (b) and (c) a single phase translucent microemulsion.
European patent publication EP 0 561 600 A2, Jahnke, Sep. 22, 1993, discloses a water in oil emulsion comprising a discontinuous aqueous phrase comprising at least one oxygen-supplying component (such as ammonium nitrate); a continuous organic phase comprising at least one carbonaceous fuel; and a minor emulsifying amount of at least one emulsifier made by the reaction of:
(A) at least one substituted succinic acylating agent, said substituted acylating agent consisting of substituent groups and succinic groups wherein the substituent groups are derived from a polyalkene, said acylating agents being characterized by the presence within their structure of an average of at least 1.3 succinic groups for each equivalent weight of substituent groups, and
(B) ammonia and/or at least one amine.
U.S. Pat. No. 5,047,175, Forsberg, Sep. 10, 1991, discloses salt compositions which comprise: (A) at least one salt moiety derived from (A)(I) at least one high-molecular weight polycarboxylic acylating agent, said acylating agent (A)(I) having at least one hydrocarbyl substituent having an average of from about 20 to about 500 carbon atoms, and (A)(II) ammonia, at least one amine, at least one alkali or alkaline earth metal, and/or at least one alkali or alkaline earth metal compound; (B) at least one salt moiety derived from (B)(I) at least one low-molecular weight polycarboxylic acylating agent, said acylating agent (B)(I) optionally having at least one hydrocarbyl substituent having an average of up to about 18 carbon atoms, and (B)(II) ammonia, at least one amine, at least one alkali or alkaline earth metal, and/or at least one alkali or alkaline earth metal compound; said components (A) and (B) being coupled together by (C) at least one compound having (i) two or more primary amino groups, (ii) two or more secondary amino groups, (iii) at least one primary amino group and at least one secondary amino group, (iv) at least two hydroxyl groups or (v) at least one primary or secondary amino group and at least one hydroxyl group. These salt compositions are disclosed to be useful as emulsifiers in water-in-oil explosive emulsions, particularly cap-sensitive water-in-oil emulsions.
U.S. Pat. No. 4,708,753, Forsberg, Nov. 24, 1987, discloses a water-in-oil emulsion comprising (A) a continuous oil phase; (B) a discontinuous aqueous phase; (C) a minor emulsifying amount of at least one salt derived from (C)(I) at least one hydrocarbyl-substituted carboxylic acid or anhydride, or ester or amide derivative of said acid or anhydride, the hydrocarbyl substituent of (C)(I) having an average of from about 20 to about 500 carbon atoms, and (C)(II) at least one amine; and (D) a functional amount of at least one water-soluble, oil-insoluble functional additive dissolved in said aqueous phase; with the proviso that when component (D) is ammonium nitrate, component (C) is other than an ester/salt formed by the reaction of polyisobutenyl (Mn=950) succinic anhydride with diethanolamine in a ratio of one equivalent of anhydride to one equivalent of amine.
U.S. Pat. No. 3,756,794, Ford, Sep. 4, 1973, discloses an emulsified fuel composition consisting essentially of (1) a major amount of a hydrocarbon fuel boiling in the range of 20-400° C. as the disperse phase, (2) 0.3% to 5% by weight of an emulsifier, (3) 0.75% to 12% by weight water, (4) 0.3% to 0.7% by weight of urea as emulsion stabilizer and (5) 0.3% to 0.7% by weight of ammonium nitrate.